hello, i am about to make the jump from PC to mac by buying an imac 24" beauty!! is a dmg file the equivilent to windows' setup installers?

[i have alot to learn!]

Similar but different. A DMG is a Disk Image, like an ISO on the PC. You double click and it mounts as a drive icon on the desktop. Inside is usually the application, and all you do to install in a most cases is drag the application out of the DMG and drop it in the Applications folder. Then you drop the open DMG in the trash and it un-mounts. Sometimes there might be a setup file in the DMG which you run to install the application, but most are just the app.